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Date:   Tue, 9 Oct 2018 16:24:40 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Heiko Carstens <heiko.carstens@de.ibm.com>
Cc:     Pingfan Liu <kernelfans@gmail.com>,
        Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        linux-next@vger.kernel.org, linux-mm@kvack.org,
        linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
        Stephen Rothwell <sfr@canb.auug.org.au>
Subject: Re: [BUG -next 20181008] list corruption with
 "mm/slub: remove useless condition in deactivate_slab"
Message-Id: <20181009162440.d40400a42544aced64f28572@linux-foundation.org>
In-Reply-To: <20181009063500.GB3555@osiris>
References: <20181009063500.GB3555@osiris>
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On Tue, 9 Oct 2018 08:35:00 +0200 Heiko Carstens <heiko.carstens@de.ibm.com> wrote:

> with linux-next for 20181008 I can reliably crash my system with lot's of
> debugging options enabled on s390. List debugging triggers the list
> corruption below, which I could bisect down to this commit:
> 
> fde06e07750477f049f12d7d471ffa505338a3e7 is the first bad commit
> commit fde06e07750477f049f12d7d471ffa505338a3e7
> Author: Pingfan Liu <kernelfans@gmail.com>
> Date:   Thu Oct 4 07:43:01 2018 +1000
> 
>     mm/slub: remove useless condition in deactivate_slab
> 
>     The var l should be used to reflect the original list, on which the page
>     should be.  But c->page is not on any list.  Furthermore, the current code
>     does not update the value of l.  Hence remove the related logic
> 
>     Link: http://lkml.kernel.org/r/1537941430-16217-1-git-send-email-kernelfans@gmail.com
>     Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
>     Acked-by: Christoph Lameter <cl@linux.com>
>     Cc: Pekka Enberg <penberg@kernel.org>
>     Cc: David Rientjes <rientjes@google.com>
>     Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>     Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
>     Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
> 
> list_add double add: new=000003d1029ecc08, prev=000000008ff846d0,next=000003d1029ecc08.
> ------------[ cut here ]------------
> kernel BUG at lib/list_debug.c:31!

Thanks much.  I'll drop
mm-slub-remove-useless-condition-in-deactivate_slab.patch.